Closed hydraulic plunger pump with high variable response speed and use method

Abstract

The invention discloses a closed hydraulic plunger pump with high variable response speed and a using method, a variable system of the plunger pump is composed of a control valve and a variable mechanism, the variable mechanism comprises a variable cylinder (10), a variable piston (11) is arranged in the variable cylinder (10), the middle of the variable piston (11) is connected with a swash plate (40) of the plunger pump, variable cavities (12) are formed in the two ends of the variable piston (11), and the variable cavities (12) are communicated with the variable cylinder (10). Copper rings (13) are arranged at the two ends of the variable piston (11), the copper rings (13) are located between the variable piston (11) and the variable cylinder (10), the variable cylinder (10) supports and seals the variable piston (11) through the copper rings (13), and the copper rings (13) are in clearance fit with the variable piston (11). The method has the advantage of high variable response speed.

Description

Technical Field

[0001] The invention belongs to the field of closed hydraulic plunger pumps, and in particular relates to a closed hydraulic plunger pump with high variable response speed and a use method thereof. Background Art

[0002] The variable system of the traditional closed hydraulic piston pump consists of a control valve and a variable mechanism. The control valve is a three-position four-way slide valve. Figure 4 As shown, the variable mechanism includes a variable cylinder, a variable piston is arranged in the variable cylinder, the middle part of the variable piston is connected to the inclined plate of the plunger pump, and variable cavities are formed at both ends of the variable piston. A step seal and a support ring made of a composite material with a relatively rough surface are arranged in the variable cylinder. The step seal and the support ring are both fitted with the outer cylindrical surface of the variable piston. The support ring supports the variable piston to move in the piston cylinder, and the step seal plays a sealing role to prevent pressure leakage in the variable cavity during variable operation.

[0003] The working principle of the variable system is: the control oil output by the oil replenishment pump is introduced into the corresponding variable chamber through the control valve, pushing the variable piston to move to the corresponding side in the variable cylinder, driving the inclination angle of the swash plate to change, thereby realizing the variable of the pump.

[0004] In some engineering applications, there are working conditions that require high-frequency reversing of hydraulic oil and thus high-frequency switching of the movement direction of the actuator. For example, when shaking the soil in a rotary drill, high-frequency reversing of hydraulic oil is required to make the winch motor switch forward and reverse at high frequency, thereby making the drill bit shake up and down at high frequency to meet the need of shaking the soil. In the past, high-frequency reversing of hydraulic oil was achieved through an open system consisting of an open electric control pump + an electric proportional reversing valve. In recent years, closed winch systems have emerged for energy-saving purposes, which require rapid bidirectional switching of the pump to achieve rapid and powerful up and down shaking of the drill rod to meet the need of shaking the soil. However, the variable response speed of the variable system of the traditional closed hydraulic piston pump is relatively slow and cannot meet such requirements. Summary of the invention

[0005] The object of the present invention is to provide a closed hydraulic piston pump with high variable response speed and a method of using the same. The present invention has the advantage of fast variable response speed.

[0006] The technical solution of the present invention is a closed hydraulic plunger pump with a high variable response speed, wherein the variable system of the plunger pump is composed of a control valve and a variable mechanism, wherein the variable mechanism includes a variable cylinder, wherein a variable piston is arranged in the variable cylinder, wherein the middle part of the variable piston is connected to the inclined plate of the plunger pump, and variable cavities are formed at both ends of the variable piston, wherein copper rings are arranged at both ends of the variable piston, and the copper rings are located between the variable piston and the variable cylinder, and the variable cylinder supports and seals the variable piston through the copper rings, and the copper rings are clearance-matched with the variable piston.

[0007] In the aforementioned closed hydraulic piston pump with high variable response speed, the control valve includes two parallel high-frequency response electric proportional pressure reducing valves, and the high-frequency response electric proportional pressure reducing valve is provided with an oil drain port T, an oil outlet port M and an oil inlet port P. The oil drain port T and the oil outlet port M are normally open, and the oil outlet port M and the oil inlet port P are normally closed. The oil drain port T is connected to the return oil circuit of the piston pump, the oil outlet port M is connected to the corresponding variable chamber, and the oil inlet port P is connected to the control oil circuit of the piston pump.

[0008] In the aforementioned closed hydraulic piston pump with high variable response speed, the control oil circuit connects the piston pump's oil replenishment pump and external pressure oil, and the pressure of the external pressure oil is ≥4MPa.

[0009] In the aforementioned closed hydraulic piston pump with high variable response speed, the two oil drain ports T are connected in parallel to the return oil circuit of the piston pump, the two oil outlets M are respectively connected to the variable chambers at both ends of the variable piston, and the two oil inlets P are connected in parallel to the control oil circuit of the piston pump.

[0010] In the aforementioned closed hydraulic plunger pump with high variable response speed, the high-frequency response proportional pressure reducing valve comprises an electromagnet, an iron core is provided in the axial direction of the electromagnet, a valve sleeve is provided at one end of the electromagnet, one end of the valve sleeve is fixed to the electromagnet, an oil outlet M is formed at the other end of the valve sleeve, an oil drain port T and an oil inlet P are provided on the side wall of the valve sleeve, a valve core connected to the iron core is provided in the valve sleeve, a pre-tightened spring is provided between the valve sleeve and the valve core, and the spring gives the valve core an elastic force to move toward the iron core;

[0011] When the electromagnet is powered off, the oil drain port T is connected to the oil outlet port M, and the oil inlet port P is disconnected from the oil outlet port M. When the electromagnet is powered on, the valve core moves a certain distance to the side of the oil outlet port M, and then the oil drain port T is disconnected from the oil outlet port M, and the oil inlet port P is connected to the oil outlet port M.

[0012] In the aforementioned closed hydraulic plunger pump with high variable response speed, a blind hole is provided on the end face of the valve core facing the oil outlet M, a first annular groove and a second annular groove are provided on the outer peripheral surface of the valve core, the first annular groove is connected to the oil drain port T, the second annular groove is located on one side of the oil inlet P, a first oil hole is provided on the bottom surface of the first annular groove, a second oil hole is provided on the bottom surface of the second annular groove, and the first oil hole and the second oil hole are both connected to the blind hole.

[0013] In the aforementioned closed hydraulic piston pump with high variable response speed, the valve core extends radially outward toward one end of the iron core to form a convex ring, and a step groove facing the electromagnet is provided in the valve sleeve, one end of the spring is connected to the bottom surface of the step groove, and the other end of the spring is connected to the convex ring.

[0014] The method of using the closed hydraulic piston pump with high variable response speed mentioned above is that the two high-frequency response electric proportional pressure reducing valves work independently. When one of the high-frequency response electric proportional pressure reducing valves is energized, the other high-frequency response electric proportional pressure reducing valve is not energized, thereby realizing the rapid variable of the piston pump.

[0015] Compared with the prior art, the present invention improves the variable system of the plunger pump on the basis of the existing plunger pump, and improves the variable mechanism and control valve of the variable system. The effects brought by the improvement are as follows:

[0016] 1) Two independently working high-frequency response electric proportional pressure reducing valves are used to form a control valve. The high-frequency response electric proportional pressure reducing valve has a higher response speed, can achieve rapid pressure build-up in the variable chamber, increases the variable response speed of the plunger pump, and can achieve independent adjustment of the pressure of the two variable chambers.

[0017] 2) The variable piston adopts copper ring for support and sealing. The friction coefficient of copper ring is smaller. At the same time, the copper ring and the variable piston are clearance matched. Oil is retained in the gap between the copper ring and the variable piston, which can reduce the friction force on the variable piston during the variable process, thereby improving the variable response speed of the plunger pump.

[0018] 3) The variable piston of the existing variable mechanism adopts a tight-fitting support ring and step seal to provide support and sealing, which has high requirements on the installation process of the variable piston. If it is not installed in place, the support ring and step seal will be cut, thereby affecting the sealing performance. The present invention adopts a copper ring that is loosely matched with the variable piston. The copper ring is not easy to be cut during installation and has good sealing performance.

[0019] 4) For the control oil entering the control valve, in addition to the original oil pump, an external pressure oil with a pressure ≥ 4MPa is added. According to the applicant's research, under normal circumstances, the oil replenishment pressure will drop significantly at the moment of forward and reverse switching of the plunger pump, affecting the pressure in the variable cavity and further affecting the variable response speed. The present invention provides control oil through the external pressure oil and the built-in oil replenishment pump, reducing the impact of the instantaneous lack of oil replenishment pressure on the variable response speed when the pump changes rapidly, thereby improving the variable response speed of the plunger pump.

[0020] In summary, the present invention has the advantage of fast variable response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the variable mechanism of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the high-frequency response electric proportional pressure reducing valve of the present invention.

[0023] Figure 3 It is the hydraulic principle diagram of the present invention.

[0024] Figure 4 It is a structural diagram of the existing variable mechanism.

[0025] The markings in the attached drawings are: 2-high-frequency response electric proportional pressure reducing valve, 10-variable cylinder, 11-variable piston, 12-variable chamber, 13-copper ring; 20-electromagnet, 21-iron core, 22-valve sleeve, 23-valve core, 24-spring, 25-blind hole, 26-first ring groove, 27-second ring groove, 28-first oil hole, 29-second oil hole, 30-convex ring, 31-step groove; 40-swash plate, 41-oil replenishing pump, 42-support ring, 43-step seal. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0027] Embodiment: A closed hydraulic piston pump with high variable response speed, wherein the variable system of the piston pump is composed of a control valve and a variable mechanism.

[0028] like Figure 1 As shown, the variable mechanism includes a variable cylinder 10, in which a variable piston 11 is arranged, the middle of the variable piston 11 is connected to the swash plate 40 of the plunger pump, and variable cavities 12 are formed at both ends of the variable piston 11. Copper rings 13 are arranged at both ends of the variable piston 11, and the copper rings 13 are fixed to the variable cylinder 10. The copper rings 13 are located between the variable piston 11 and the variable cylinder 10. The variable cylinder 10 supports and seals the variable piston 11 through the copper rings 13, and the copper rings 13 and the variable piston 11 are clearance-matched.

[0029] The control valve includes two parallel high-frequency response electric proportional pressure reducing valves 2, such as Figure 2 and Figure 3 As shown, the high-frequency response electric proportional pressure reducing valve 2 is provided with an oil drain port T ( Figure 2 As shown at T in the middle), oil outlet M ( Figure 2 M in the middle) and the oil inlet P ( Figure 2 As shown at P in the figure, the oil drain port T and the oil outlet port M are usually open, while the oil outlet port M and the oil inlet port P are usually disconnected.

[0030] The two oil drain ports T are connected in parallel to the return oil circuit of the plunger pump, and reach the return oil tank through the return oil circuit. The two oil outlets M are respectively connected to the variable chambers 12 at both ends of the variable piston 11. The two oil inlets P are connected in parallel to the control oil circuit of the plunger pump. The control oil circuit is connected to the original built-in oil replenishment pump 41 of the plunger pump and externally connected to the pressure oil. The oil replenishment pump 41 and the external pressure oil jointly provide control oil for the control oil circuit. The oil supply pressure of the external pressure oil is ≥4MPa.

[0031] The high-frequency response electric proportional pressure reducing valve 2 comprises an electromagnet 20, an iron core 21 is axially arranged on the electromagnet 20, a valve sleeve 22 is arranged at one end of the electromagnet 20, one end of the valve sleeve 22 is fixed to the electromagnet 20, an oil outlet M is formed at the other end of the valve sleeve 22, an oil drain port T and an oil inlet P are arranged on the side wall of the valve sleeve 22, a valve core 23 abutting against the iron core 21 is arranged in the valve sleeve 22, a pre-tightened spring 24 is arranged between the valve sleeve 22 and the valve core 23, the spring 24 gives the valve core 23 an elastic force to move toward the iron core 21, so that the valve core 23 and the iron core 21 are closely attached;

[0032] When the electromagnet 20 is powered off, the oil drain port T is connected to the oil outlet port M, and the oil inlet port P is disconnected from the oil outlet port M. When the electromagnet 20 is powered on, the valve core 23 moves a certain distance toward the oil outlet port M, and then the oil drain port T is disconnected from the oil outlet port M, and the oil inlet port P is connected to the oil outlet port M.

[0033] A blind hole 25 is provided on the end surface of the valve core 23 facing the oil outlet M, and a first annular groove 26 and a second annular groove 27 are provided on the outer peripheral surface of the valve core 23. The first annular groove 26 is connected to the oil drain port T, and the second annular groove 27 is located on one side of the oil inlet P. A first oil hole 28 is provided on the bottom surface of the first annular groove 26, and a second oil hole 29 is provided on the bottom surface of the second annular groove 27. The first oil hole 28 and the second oil hole 29 are both connected to the blind hole 25.

[0034] The valve core 23 extends radially outward at one end toward the iron core 21 to form a convex ring 30 . The valve sleeve 22 is provided with a step groove 31 toward the electromagnet 20 . One end of the spring 24 is pressed against the bottom surface of the step groove 31 , and the other end of the spring 24 is pressed against the convex ring 30 .

[0035] How to use the plunger pump: The two high-frequency response electric proportional pressure reducing valves 2 work independently. When one of the high-frequency response electric proportional pressure reducing valves 2 is energized, the other high-frequency response electric proportional pressure reducing valve 2 is not energized, thereby realizing rapid variable of the plunger pump.

[0036] The working principle of high-frequency response electric proportional pressure reducing valve 2: Figure 2 As shown, the electromagnet 20 is energized, and the iron core 21 pushes the valve core 23 to move to the left to overcome the elastic force of the spring 24. As the current increases, the thrust of the iron core 21 on the valve core 23 increases, further compressing the spring 24, and the valve core 23 moves further to the left, so that the oil outlet M is connected with the oil inlet P, and the control oil enters the corresponding variable chamber 12 from the oil inlet P through the oil outlet, pushing the variable piston 11 to move, so that the pump displacement changes.

[0037] like Figure 3As shown, when the left high-frequency response electric proportional pressure reducing valve 2 (referred to as the left valve) is powered on and the right high-frequency response electric proportional pressure reducing valve 2 (referred to as the right valve) is powered off. The oil inlet P of the left valve communicates with the oil outlet M, and the control oil enters the left variable chamber 12, pushing the variable piston 11 to the right. The hydraulic oil in the right variable chamber 12 flows from the oil outlet M and the oil drain port T of the right valve to the return oil tank. At this time, the plunger pump outputs high-pressure oil at port A. When the left valve is powered off and the right valve is powered on, the oil inlet P of the right valve communicates with the oil outlet M, and the control oil enters the right variable chamber 12, pushing the variable piston 11 to the left. The hydraulic oil in the left variable chamber 12 flows from the oil outlet M and the oil drain port T of the left valve to the return oil tank. At this time, the plunger pump outputs high-pressure oil at port B. Rapid variable switching of the plunger pump is achieved by rapidly alternating the power on and off of the two electromagnets 20.

[0038] The gap between the copper ring 13 and the variable piston 11 is set to 0.035mm, for example. When the variable is changed, there is oil ≥4MPa in the corresponding variable cavity, so that a small amount of oil leaks into the pump housing through the gap between the copper ring 13 and the variable piston 11, while ensuring the establishment of a stable pressure in the variable cavity, providing lubrication for the movement of the variable piston and reducing the friction coefficient.

[0039] The variable mechanism in the embodiment is similar to Figure 4 A comparison of existing variable mechanisms is shown:

[0040] In the existing variable mechanism, the support ring 42 provides support and guidance for the variable piston 11, and the step seal 43 provides sealing between the variable piston 11 and the variable cylinder 10. The support ring 42, the step seal 43 and the variable piston 11 are interference fit, and the support ring 42 has a rough surface and a large friction coefficient. During the variable process, a large friction force is generated on the variable piston 11, thereby reducing the variable speed of the plunger pump.

[0041] In the variable mechanism in the embodiment, a copper ring 13 is used to provide support, guidance and sealing for the variable piston 11. The copper ring 13 is lubricating and has a small friction coefficient. At the same time, the copper ring 13 and the variable piston 11 are clearance-matched. When the variable is changed, the gap between the copper ring 13 and the variable piston 11 is lubricated by oil, and the friction resistance is smaller, thereby improving the variable speed of the plunger pump.

[0042] In addition, in the existing variable mechanism, when installing the guide ring and step seal, the variable piston is easy to cut the support ring and step seal, causing sealing failure; the use of copper rings can avoid this problem.

[0043] In the description of the embodiments, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation.

Claims

1. A closed hydraulic piston pump with high variable response speed, wherein the variable system of the piston pump is composed of a control valve and a variable mechanism, wherein the variable mechanism comprises a variable cylinder (10), wherein a variable piston (11) is arranged in the variable cylinder (10), wherein the middle of the variable piston (11) is connected to a slanted plate (40) of the piston pump, and both ends of the variable piston (11) form variable chambers (12), wherein the variable mechanism comprises: Copper rings (13) are provided at both ends of the variable piston (11). The copper rings (13) are located between the variable piston (11) and the variable cylinder (10). The variable cylinder (10) supports and seals the variable piston (11) through the copper rings (13). The copper rings (13) and the variable piston (11) are clearance-matched.

2. The closed hydraulic piston pump with high variable response speed according to claim 1, characterized in that: The control valve comprises two parallel high-frequency response electric proportional pressure reducing valves (2), and the high-frequency response electric proportional pressure reducing valves (2) are provided with an oil drain port T, an oil outlet port M and an oil inlet port P. The oil drain port T and the oil outlet port M are normally open, and the oil outlet port M and the oil inlet port P are normally disconnected. The oil drain port T is connected to the return oil circuit of the plunger pump, the oil outlet port M is connected to the corresponding variable chamber (12), and the oil inlet port P is connected to the control oil circuit of the plunger pump.

3. The closed hydraulic piston pump with high variable response speed according to claim 2, characterized in that: The control oil circuit is connected to the oil replenishment pump (41) of the plunger pump and external pressure oil, and the pressure of the external pressure oil is ≥4MPa.

4. The closed hydraulic piston pump with high variable response speed according to claim 2, characterized in that: The two oil drain ports T are connected in parallel to the oil return circuit of the plunger pump, the two oil outlet ports M are respectively connected to the variable chambers (12) at both ends of the variable piston (11), and the two oil inlets P are connected in parallel to the control oil circuit of the plunger pump.

5. The closed hydraulic piston pump with high variable response speed according to claim 2, characterized in that: The high-frequency response electric proportional pressure reducing valve (2) comprises an electromagnet (20), an iron core (21) is axially arranged on the electromagnet (20), a valve sleeve (22) is arranged at one end of the electromagnet (20), one end of the valve sleeve (22) is fixed to the electromagnet (20), the other end of the valve sleeve (22) forms an oil outlet M, an oil drain port T and an oil inlet P are arranged on the side wall of the valve sleeve (22), a valve core (23) connected to the iron core (21) is arranged in the valve sleeve (22), a pre-tightened spring (24) is arranged between the valve sleeve (22) and the valve core (23), and the spring (24) gives the valve core (23) an elastic force to move toward the iron core (21); When the electromagnet (20) is powered off, the oil drain port T is connected to the oil outlet port M, and the oil inlet port P is disconnected from the oil outlet port M. When the electromagnet (20) is powered on, the valve core (23) moves a certain distance toward the oil outlet port M, and then the oil drain port T is disconnected from the oil outlet port M, and the oil inlet port P is connected to the oil outlet port M.

6. The closed hydraulic piston pump with high variable response speed according to claim 5, characterized in that: A blind hole (25) is provided on the end surface of the valve core (23) facing the oil outlet M, a first annular groove (26) and a second annular groove (27) are provided on the outer peripheral surface of the valve core (23), the first annular groove (26) is connected to the oil drain port T, the second annular groove (27) is located on one side of the oil inlet P, a first oil hole (28) is provided on the bottom surface of the first annular groove (26), a second oil hole (29) is provided on the bottom surface of the second annular groove (27), and both the first oil hole (28) and the second oil hole (29) are connected to the blind hole (25).

7. The closed hydraulic piston pump with high variable response speed according to claim 5, characterized in that: One end of the valve core (23) facing the iron core (21) extends radially outward to form a convex ring (30); a step groove (31) facing the electromagnet (20) is provided in the valve sleeve (22); one end of the spring (24) is connected to the bottom surface of the step groove (31); and the other end of the spring (24) is connected to the convex ring (30).

8. The method for using the closed hydraulic piston pump with high variable response speed according to any one of claims 2 to 7, characterized in that: The two high-frequency response electric proportional pressure reducing valves (2) work independently. When one of the high-frequency response electric proportional pressure reducing valves (2) is energized, the other high-frequency response electric proportional pressure reducing valve (2) is not energized, thereby realizing the rapid variable of the plunger pump.

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